Most people think of Flash as giving "pretty pictures" (or perhaps these days "annoying intros") but in fact Flash offers developers a sophisticated programming environment that is optimised for the display of graphical information and which is tailored for operation over the Internet.
Flash makes use of Vector graphics to specify images. These describe a picture in terms of shapes and key points rather than pixel-by-pixel. The Flash player which is available to over 98% of users, downloads the picture description, and then draws it itself. Because of this Flash files are much smaller, and combined with the drawing ability, ideally suited to animation. The small size of Flash files means we can achieve faster downloads, and that we can get in more detail in the same bandwidth.Within the Flash player it is possible to describe an image as a series of pictures layered on top of each other. Again, this enables us to split an animation into separate layers and to allow the user to decide which they need to download. Even if they download all the data, because Flash is interactive we can add menus and buttons that allow users to toggle the display of each layer on and off.
Because Flash offers a programming environment, we can do so much more. For example we can add pan and zoom functions. So as well as being able to toggle layers on and off, you can tailor the view of that data to meet your particular needs. And because this is all being done inside the Flash client, you can do all this without maintaining your link to the Internet, saving on connection costs and further download costs.